/*
* Copyright 2022 Axel Waggershauser
* Copyright 2022 Markus Fisch
*/
// SPDX-License-Identifier: Apache-2.0

package com.example.zxingcppdemo

import android.content.Context
import android.graphics.Canvas
import android.graphics.Paint
import android.graphics.Path
import android.graphics.PointF
import android.graphics.Rect
import android.util.AttributeSet
import android.view.View
import androidx.camera.core.ImageProxy
import kotlin.math.max
import kotlin.math.min

class PreviewOverlay constructor(context: Context, attributeSet: AttributeSet?) :
	View(context, attributeSet) {

	private val paintPath = Paint(Paint.ANTI_ALIAS_FLAG).apply {
		style = Paint.Style.STROKE
		color = 0xff00ff00.toInt()
		strokeWidth = 2 * context.resources.displayMetrics.density
	}
	private val paintRect = Paint().apply {
		style = Paint.Style.STROKE
		color = 0x80ffffff.toInt()
		strokeWidth = 3 * context.resources.displayMetrics.density
	}
	private val path = Path()
	private var cropRect = Rect()
	private var rotation = 0
	private var s: Float = 0f
	private var o: Float = 0f

	fun update(viewFinder: View, image: ImageProxy, points: List<List<PointF>>) {
		cropRect = image.cropRect
		rotation = image.imageInfo.rotationDegrees
		s = min(viewFinder.width, viewFinder.height).toFloat() / image.height
		o = (max(viewFinder.width, viewFinder.height) - (image.width * s).toInt()).toFloat() / 2

		path.apply {
			rewind()
			points.forEach {
				if (!it.isEmpty()) {
					val last = it.last()
					moveTo(last.x, last.y)
					for (p in it) {
						lineTo(p.x, p.y)
					}
				}
			}
		}
		invalidate()
	}

	override fun onDraw(canvas: Canvas) {
		canvas.apply {
			// draw the cropRect, which is relative to the original image orientation
			save()
			if (rotation == 90) {
				translate(width.toFloat(), 0f)
				rotate(rotation.toFloat())
			}
			translate(o, 0f)
			scale(s, s)
			drawRect(cropRect, paintRect)
			restore()

			// draw the path, which is relative to the (centered) rotated cropRect
			when (rotation) {
				0, 180 -> translate(o + cropRect.left * s, cropRect.top * s)
				90 -> translate(cropRect.top * s, o + cropRect.left * s)
			}
			scale(s, s)
			drawPath(path, paintPath)
		}
	}
}
